Aeroplane construction



Oct. 13, 1931. H. ALFARO 1,827,181

AEROPLANE CONSTRUCTI ON Filed Oct. 30, 1930 3 Sheets-Sheet l V MW 5 u Wu7 p Mn MAYA fig 3 6 j INVENTOR /4 BY 2 ATTORNEYE? Oct. 13, 1931. H.ALFARO 1,327,181

AEROPLANE CONSTRUCTION Filed Oct. 50, 1930 s Sheets-Sheet 2 INVENTORATTORNEY5 Oct. 13, 193 1. H, ALFARO 1,827,181

AEROPLANE CONSTRUCTION Filed Oct. 30, 1930 3 Sheets-Sheet 3 INVENTOR WATTORNEY Patented Oct-.13; 1931 UNITED STATES nnnacnro AL-FARO, 01- EASTCLEVELAND, 01110 AEROPLAN E CONSTRUCTION Application filed October 30,1930. Serial No. 492,235.

failure of one or more of the structural elements composing the framework.

A further object is to provide an aeroplane especially suitable formilitary purposes by so constructing the frame work that if anystructural member of the framework should be severed by the explosion ofa shell or burst of machine gun bullets, the load will be car ried b theother frame members, so that continue flight is possible.

A further object is to=provide a fuselage frame so constructed as toprovide maximum rigidity in the portion of the fuselage to which thewings are attached and to so construct the wings as to provide maximumrigidity at the inner ends thereof which are connected to the fuselage.

A further object is to provide a frame work i composed wholly of lightstructural members so in which the necessaryrigidity is supplied bysystems of diagonal braces.

With the above and other objects in view, the invention may be said tocomprise the construction as illustrated in the accompanying drawingshereinafter described and particularly set forth in the appended claims,together with such variations and modifications thereof as will beapparent to one skilled in the art to which the invention ap- 'pertains.

Reference should be had to the accompanying drawings forming a part ofthis specification in which:

Figure 1 is a top plan view of an aeroplane embodying the invention.

Fig. 2-is a side elevation of. the fuselage frame.

Fig. 3 is a transverse section through'the 10 fuselage frame on anenlarged scale.

' versely through one of the wings. 1

Fig. 4 is a transverse section through one of the side panels of thefuselage frame.

'Fi 5 is a p'ers ective view showing the I attac ment of the races tothe longrons in the fuselage frame. F

Fig. 6 is a perspective view showing a slightly modified construction inwhich one piece angle shaped longrons are employed.

Fig. 7 is a perspective view showing the connection of the braces at acrossing point. no

Figs. 8 to 13, inclusive, are detail views showing various structuralshapes which may be employed for the braces.

Fig. 14 is a vertical section taken trans- Fig. '15 is a plan viewshowing a wing with a slightly modified bracing system.

Fig. 16 is a perspective view of one of the wing beams. r F1 17 is asectional view showing a modi- 7Q fied orm of wing having a controllingflap along its trailing edge. Fi 18 is a perspective view showing theflap ame work. I I

.Fig. 19 is a perspective view showing a 7 slightly modified flapconstruction. In the accompanying drawings, the fuse lage is indicatedby the reference numeral 1 and the wings attached to the fuselage by thereferencenumeral2. Thedrawingsshowonly an I the structural frame work ofthe aeroplane, since the present invention relates exclusively to theconstruction of the said structural frame work.

As best shown in Figs. 2 and 3, the fuselage as 1 has longrons 2 whichextend the full length thereof at the intersections of the side wallswith the top and bottom walls and these longrons are preferably eachcomposed of two angle bars 4 which have flanges 5 and 6 9e disposed atanangle of approximately The edges of the flanges are preferably rolledoper to provide beads 7 along the edges there-: 0

The longrons are arranged with their as flanges 5 back to back and arerigidly secured together by a row of rivets 8. The flanges 6 of the bars4 forming each of the longrons are disposed at right angles to eachother and the longrons are connected by means of di we agonal braces 9which are arranged in crossing relation. The braces 9 are preferablychannel shaped structural members having curled flanges 10 which providestrengthening beads along the edges thereof. The braces 9 are arrangedin crossing relation and, preferably, with the end of each brace joinedto the end of an oppositely inclined bra'ce at its point of connectionwith the longrons.

As shown in Fig. 6, the braces 9 are flattened at their ends andoppositely inclined braces are attached together and to a flange 6 ofthe longron by any suitable means such as rivets 11.

The crossing braces are arranged back to back and secured together byany suitable means such as a rivet 12 at each crossing point, as shownin Fig. 7.

The use of two part longrons permits the separate fabrication of each ofthe four panels of the fuselage frame, the braces 9 being rivetedtogether and to the flanges 6 of the angle bars 4, as shown in Fig. 4,after which the panels are assembled and the flanges 5 of the angle barsare riveted together at the corners of the frame to complete theassembly. lln some instances, it may be desirable to employ one piecelongrons in which case a structural member of angle shape such asindicated by the numeral 13 in Fig. 6 is preferred, the member 13 havingflanges 14 which are rolled over at their edges to provide beads 15. Inthis modification, the diagonal braces 9 are riveted to the flanges 14of the longron 13, which are disposed at right angles to each other.

The longrons are preferably formed of sheet metal such as an aluminumalloy stainless steel or other alloys and the braces 9 are preferablyformed of the same material, although wooden members may be employed, ifdesired. i

It will be understood that the fastening I means employed for securingthe braces to the longrons and to each other will be that best suitedfor the particular material of which these members are composed. Forinstance, when stainless steel or other easily weldable material isemployed, the members may be joined by electrically welded spots insteadof rivets.

Various structural shapes may be employed for the braces such as theshape 16 shown in Fig. 8, 17 shown in Fig. 9, 18 shown in Fig. 10, 19shown in Fig. 11, 20 shown in Fig. 12, or 21 shown in Fig; 13.

The rivets 12 connecting the braces 9 at their crossing points arepreferably made of a relatively soft metal such as aluminum while therivets 11 connecting the braces to the longrons are preferably of aharder metal .such as an aluminum copper alloy or iron, this beingdesirable for simplicity of fabrication.

The braces 9 are preferably so arranged in saaiei the side walls of thefuselage as to provide maximum strength and rigidity in the portions ofthe fuselage where the stresses are highest. This result is obtained byspacing the braces closer together and at a greater angle with respectto the longrons in the portion of the fuselage to which the wings orother highly stressed members are attached and gradually increasing thespacing and decreasingthe angle of inclination toward the ends of thefuselage, as clearly shown in Fig.2.

The wings 2 are provided with two or more spaced longitudinal beams 22,each of which is of skeleton construction having top and bottom memberseach composed of two angle bars 23 secured together back to back anddiagonal braces 24 which are arranged in crossing relation and securedbetween the flanges of the angle bars 23 by means of rivets 25. Theangle members 23 and braces 24 are preferably made of a sheet metalcomposed of an aluminum alloy or rustless steel and the braces may be ofthe same shape as the braces 9 of the fuselage.

The braces 24 are arranged back to back and are attached at theircrossing points by means of rivets 26. The beams 22, as shown in Fig. 14are held against relative vertical movements by means of rigid crossmembers 27 extending through and connected to the beams .intermediatethe tops and bottoms thereof. The top wall of the wing is reinforced bytop braces 28 which extend diagonally across the tops of the beams incrossing relation from adjacent the forward; edge to adjacent thetrailing edgeof the win The bottom wall of the wing is reinforce bydiagonal braces 29 which extend across the bottoms of the beams 22 fromadjacent the forward edge to adjacent the trailing edge of the wing andwhich are also disposed in crossing relation.

The top and bottom braces 28 and 29 are preferably inclined oppositelywith respect to the beams and are rigidly attached to the beams. Thebraces 28 and 29 are so arranged that the ends of the top braces adjoinends of oppositely inclined bottom braces along the front and rear edgesof the wing. The top braces 28 are so arranged that the outenonesincline in an inward direction from fore to aft in the wing while theouter diagonal braces of the lower face of the wing are inclinedoutwardly from the leading edge toward the trailing edge, the directionof the braces being in the general direction of the stream lines of flowalong the upper and lower faces of the wing.

The braces of the wings are preferably so arranged as to provide maximumrigidity adjacent the inner ends of the wings which are attached to thefuselage. This result is accomplished by, spacing the braces closelytogether and at a high angle of inclination with respect to the beams22, adjacent the inner ends of the wings and gradually decreasing theinclination and increasing the spacing of the braces toward the outerends or tips of the wings. The differential spacing of the wing braces,while advantageous, is not essential to the invention and these bracesmay, if

desired, be arranged with uniform angularity and uniformspacing, asshown in Fig. of the drawings in which the top and bottom braces 31 and32 are shown so arranged.

The wings may be provided with controlling flaps along their rear edges,as shown at r 33 in Fig. 17, in which case, the flap is preferplacedcloser together and in crossing relation in both the top and bottomwall. As shown in Fig. 19, the top wall is provided witha system ofcrossing diagonal braces 40 and the bottom wall with a similar system ofcrossing braces 41.

It will be apparent that the present invention provides a structuralframework for aeroplanes which can be quickly and easily fabricated,which is of low weight, but which nevertheless possesses great strengthand rigidity and is capable of withstanding extreme stresses.

Furthermore it is to be understood that the particular "form ofapparatus shown and described, and the particular procedure set forth,are presented for purposes of explanation and illustration and thatvarious modifications of said apparatus and procedure can be madewithout departing from my inven-' tion as defined in the appendedclaims.

What I claim is:

1. An aeroplane having a fuselage, the frame work of which consists oflongrons at the intersection ,of the side walls with the top and bottomwalls and a system of diagonal braces connecting the longrons across thetop, bottom and sides of the frame, each brace being connected at itsends to the longrons and to oppositely inclined braces and intermediateits ends to an. oppositely inclined brace, and wings having longitudinalbeams which have top and bottom members and webs composed of crossingdiagonal braces and top and bottom walls having braces extendingdiagonally across the same and connected to the top and bottom membersofthe beams.

2. An aeroplane having a fuselage, the frame work of which consists oflongrons at the intersection of the side walls with the top and bottomwalls and'a, system of diagonal braces connecting the longrons acrossthe top, bottom and sides of the frame, each brace being connected atits ends to the longrons and to oppositely inclined braces andintermediate its ends to an oppositely inclined brace, and wings havinglongitudinal beams which have top and bottom members and webs composedof crossing diagonal braces and top and bottom walls having bracesextending diagonally across the same and connected to the top and bottommembers of the beams, the outer braces of the top wall of each wingbeing oppositely inclined with respect to th outer braces of the bottomwall. I

3. An aeroplane having a fuselage, the framework of'which consists oflongrons at the .intersection of the side walls with the top and bottomwalls and a system of diagonal braces connecting the longe'rons acrossthe top, bottom and sides of the frame, each brace being. connected atits ends to the longrons and to oppositely inclined braces andintermediate its ends to an oppositely inclined brace, the braces at thesides of the fuselage frame being closely spaced and at relatively highangles of inclination in the portion of the fuselage to which the wingsare attached and of progressively less inclination towardthe ends of theframe, and wings having longitudinal beams which have top and bottommembers and web-s composed of crossing diagonal braces and top andbottom walls having braces extending diagonally across the same andconnected to the top and bottom members of the beams.

4. An aeroplane having a fuselage, the framework of which consists oflongrons at the intersection of the side walls with the top and bottomwalls and a system of diagonal braces connecting the longrons across thetop, bottom and sides of the frame, each brace being connected at itsends to the longerons and to oppositely inclined braces and intermediateits ends to an oppositely in-.

clined brace, the braces at the sides of the fuselage frame beingclosely spaced and at relatively high angles of inclination in theportion of the fuselage to which the wings are attached and ofprogressively less inclination toward the ends of the frame, and wingshaving longitudinal beams which have top and framework of which consistsof longrons at the intersection of the side walls with the top andbottom walls and a system of diagonal braces connecting the longronsacross the top, bottom and sides of the frame, each brace beingconnected at its ends to the longrons and to oppositely inclined bracesand intermediate its ends to an oppositely inclined brace, and wingshaving longitudinal beams which have top and bottom members and webscomposed of crossing diagonal braces and top and bottom walls havingbraces extending diagonally across the same and connected to the top andbottom members of the beams, the frame members of the fuselage and wingsbeing all in the form of flanged sheet metal structural shapes.

6. An aeroplane having a fuselage, the framework of which consists oflongrons at the intersection of the side walls with the top and bottomwalls and a system of diagonal braces connecting the longrons across thetop, bottom and sides of the frame, each brace being connected at itsends to the longrons "and to oppositely inclined braces and intermediateits ends to an oppositely inclined brace. I

7. An aeroplane having a fuselage, the framework of which consists oflongrons at the intersection of the side walls with the top and bottomwalls and a system of diagonal braces connecting the longrons acrossthetop, bottom and sides of the frame, each brace being connected at itsends tothe longrons and to oppositely inclined braces and intermediateits ends to an oppositely inclined brace,-said longrons and braces beingflanged sheet metal members, the braces of each fuselage wall beingarranged back to back and attached together at their crossing points,oppositely inclined braces having their ends riveted together and to thelongrons.

8. An aeroplane having a fuselage, the framework of which consists oflongrons at the intersection of the side walls with the top and bottomwalls and a system of diagonal braces connecting the longrons across thetop, bottom and sides of the frame, each brace being connected at itsends to the longrons and to oppositely inclined braces and intermediateits ends to an oppositely inclined brace, said longrons and braces beingflanged sheet metal members, the braces of each fuselage wall beingarranged back to back and attached together at their crossing points,oppositely inclined braces having their ends attached together and tothe longrons, the inclination of the braces with respect to the longronsgradually decreasing toward the rear end of the fuselage.

9. An aeroplane having a fuselage, the framework of which consists oflongrons at the intersection of the side walls with the top and bottomwalls and a system of diagonal aeemsi pair of angle members havingflanges attached together back to back.

10. An aeroplane having a fuselage, the framework of which consists oflongrons at the intersection of the side walls with the top and bottomwalls and a system of diagonal braces connecting the longrons across thetop, bottom and sides of the frame, each brace being connected at itsends to the longrons and intermediate its ends to an oppositely inclinedbrace, said longrons and braces being flanged sheet metal members, thebraces of each fuselage wall being arranged back to back and attachedtogether at their crossing points, oppositely inclined braces havingtheir ends attached together and to the longrons, each of said longronsconsisting of a pair of angle members having flanges attached togetherback to back.

11. An aeroplane having a fuselage, the framework of which consists oflongronsvat the intersection of the side walls with the top and bottomwalls anda system of diagonal braces connecting the longrons across thetop, bottom and sides of the frame, each brace being connected at itsends to the longrons and intermediate its ends to an oppositely inclinedbrace, said longrons and braces being flanged sheet metal members, thebraces of each fuselage wall being arranged back to back and rivetedtogether at their crossing points, oppositely inclined braces havingtheir ends riveted together and to the longrons, the rivets'connectingthe braces at their crossing points being formed of a relatively softmetal. Y

12. An aeroplane having a fuselage, the framework of which consists oflongrons at the intersection of the side walls with the top and bottomwalls and a system of diagonal braces connecting the longrons across thetop, bottom and sides of the frame, each brace being connected at itsends to the longrons and to oppositely inclined braces and intermediateits ends to an oppositely inclined brace, said longrons and braces beingflanged sheet metal members, the braces of each fuselage wall beingarranged back to back and riveted together at their crossing points,oppositely inclined braces having their ends riveted together and to thelongrons, the rivets connecting the braces at their crossing pointsbeing formed of a relatively soft metal, the rivets joining the bracesto the longrons being formed of a harder metal.

13. An aeroplane having a fuselage, the framework of which consists oflongrons at the intersection of the side walls with the top and bottomwalls and a system of diagonal iIO braces connecting the longrons acrossthe top, bottom and sides of the frame, each brace being connected atits ends to the longrons and to oppositely inclined braces andintermediate its ends to an oppositely inclined brace, said longrons andbraces being flanged sheet metal members, the braces of of each fuselagewall being arranged back to back and riveted together at their crossingpoints, oppositely inclined braces having their ends riveted togetherand to the longrons, the inclination of the braces with respect to thelongrons gradually decreasing toward the rear end of the fuselage, therivets connecting the braces at their crossing points being formed of arelatively soft metal and the rivets joining the braces to the longronsbeing of a harder metal.

14. In an aeroplane, a wing having longitudinal beams which have top andbottom members and webs composed of crossing diagonal braces, connectingthe top and bottom members, and inclined braces extending across the topand bottom of the wing and joined to said beams.

15. In an aeroplane, a wing having longitudinal beams which have top andbottom members and webs composed of crossing diagonal braces, connectingthe top and bottom members, and inclined 'braces extending across thetop and bottom of the wing and joined to said beams, the outer braces atthe top of the wing being inclined at an angle opposite that of theouter brace members at the bottom of the wing.

, 16. In an aeroplane, a wing having longitudinal beams which have topand bottom members and webs composed of crossing diagonal braces,connecting the top and bottom members, and inclined braces extendingacross the top and bottom of the wing an aimed to said beams, saidmembers and braces ing all in the form of flanged sheet metal bars.

17. In an aeroplane, a wing having longitudinal beams which have top andbottom members and webs composed of crossing diagonal braces, connectingthe top and bottom members, and inclined braces extending across the topand bottom of the wing and joined to said beams, the outer braces at thetop of the wing being inclined at an angle opposite that of the outerbrace members at the bottom of the wing, the ends of oppositely inclinedbraces of the top and bottom walls adjoining near the front and rearedges of the wing.

18. In an aeroplane, a wing having longitudinal beams which have top andbottom members and webs composed of crossing diagonal braces, connectingthe top and bottom members, and inclined braces extending across the topand bottom of the wing and joined to said beams, the outer braces at thetop of the wing being inclined at an angle opposite that of the outerbrace members at the bottom of the wing, inclination of said braces withrespect to the beams gradually decreasing toward the outer ends of thewings and the spacing of said braces gradually decreasing toward theinner end of the wing.

19. In an aeroplane, a wing having longitudinal beams which have top andbottom members and webs composed of crossing diagonal braces connectingthe top and bottom members, inclined braces extending across the top andbottom of the wing and joined to said beams, and cross membersconnecting the beams intermediate the top and bottom members thereof.

20. In an aeroplane, a wing having longitudinal beams which have top andbottom members and webs composed of crossing diagonal braces, connectingthe top and bottom members, and inclined braces extending across the topand bottoms of the wing and joined to said beams, the outer braces atthe top of the wing extending inwardly from fore to aft in the wing andthe outer braces at the bottom of the wing having an oppositeinclination.

In testimony whereof I aflix my signature.

HERACLIO ALFARO.

